Add-on montelukast in antihistamine-resistant chronic idiopathic urticaria

Antihistamines (AH) alleviate pruritus and decrease the incidence of hives in patients with chronic idiopathic urticaria (CU). However, some patients do not respond completely to this therapy. We hypothesized that some of them might benefit from the addition of leukotriene receptor antagonists (LA).

We screened patients diagnosed and treated for CU and selected those that had symptoms despite antihistamine treatment. In a double-blind crossover study, patients took the leukotriene antagonist montelukast (10 mg per day) or placebo. Efficacy was assessed by a symptom score.

In a group of 22 patients, the symptom score was not significantly different between periods using montelukast (48.8; 0-214) or placebo (68.5; 0-230). However in the subgroup of five patients with the most severe urticaria, defined as patients with symptom scores in the upper quartile at inclusion in the study, montelukast (41; 11 214) was superior to placebo (95.5; 48 230; p < 0.05), but only when using an in-house symptom score questionnaire and not when using a validated urticaria activity score questionnaire.

We showed that in patients with antihistamine-resistant CU the addition of montelukast significantly diminished symptoms in only a small minority of patients. However, response to add-on montelukast was seen in the subgroup of patients with particularly severe disease. To confirm this observation, a study with a larger group of patients is warranted.